A semiconductor integrated circuit (IC) has a large number of electronic components, such as transistors, logic gates, diodes, wires, etc., that are fabricated by forming layers of different materials and of different geometric shapes on various regions of a silicon wafer.
Many phases of physical design may be performed with computer aided design (CAD) tools or electronic design automation (EDA) systems. To design an integrated circuit, a designer first creates high level behavior descriptions of the IC device using a high-level hardware design language. An EDA system typically receives the high level behavior descriptions of the IC device and translates this high-level design language into netlists of various levels of abstraction using a computer synthesis process. A netlist describes interconnections of nodes and components on the chip and includes information of circuit primitives such as transistors and diodes, their sizes and interconnections, for example.
An integrated circuit designer may uses a set of layout EDA application programs to create a physical integrated circuit design layout from a logical circuit design. The layout EDA application uses geometric shapes of different materials to create the various electrical components on an integrated circuit and to represent electronic and circuit IC components as geometric objects with varying shapes and sizes. After an integrated circuit designer has created an initial integrated circuit layout, the integrated circuit designer then verifies and optimizes the integrated circuit layout using a set of EDA testing and analysis tools. Verification may include, for example, design rule checking to verify compliance with rules established for various IC parameters.
Typically, geometric information about the placement of the nodes and components onto the chip is determined by a placement process and a routing process. The placement process is a process for placing electronic components or circuit blocks on the chip and the routing process is the process for creating interconnections between the blocks and components according to the specified netlist.
Based upon this geometric information, photomasks are created for lithographic manufacturing of the electronic product. A photomask, or more simply a “mask,” provides the master image of one layer of a given integrated chip's physical geometries. A typical photolithography system projects UV light energy on to and through the mask in order to transmit the mask pattern in reduced size to the wafer surface, where it interacts with a photosensitive coating on the wafer.
The manufacturability of modern IC designs using conventional optical lithography technology is increasingly being challenged by the sub wavelength, or low-k1, dimensions of the critical IC feature geometries. Not only are the critical dimension feature geometries decreasing in size in accordance with, or even faster than, Moore's Law predictions, the already large number of these feature geometries is growing at a dramatic rate as well. Furthermore, due to the necessity to mitigate optical proximity effect distortions through resolution enhancement techniques at the mask level, the overall polygonal figure count is skyrocketing. These critical feature geometries are patterned far more precisely as well due to the severity and sensitivity of the non-linear imaging. Extreme precision is required for sub wavelength, or low-k1, applications due to highly non-linear imaging behaviors which often magnify mask errors by large factors and non-intuitive manners.
In deep submicron design, a significant amount of time and effort is usually spent dealing with design manufacturability rules. The problem is that conventional approaches for handling design rules tend to break down when handling deep submicron designs.
For example, during the placement and routing process, conventional routers only act and analyze routes based upon individual objects in the layout. Each separate object in the layout would be individually considered by the router as it decides the best route to and through these objects. This is true for conventional routers, regardless of whether the router is a gridded or gridless router.
The present invention is directed to an improved method, system, and computer program product for performing layout, placement, and routing for electronic designs. According to some embodiments, multiple objects are considered as a collective object or shape, based upon the proximity of one or more of the objects to one or more other objects. The type and/or configuration of the collective object is based, for example, upon the type of rule that is being considered for the layout, placement, or routing operation. Other and additional objects, features, and advantages of the invention are described in the detailed description, figures, and claims.